A period of heightened Soviet-U.S. tensions precipitated by the Soviet Union's 1 May 1960 downing of an American U-2 reconnaissance plane that was clandestinely taking high-altitude photographs of Soviet defense installations. The plane's wreckage, together with the confession of the captured pilot, offered irrefutable proof of previously unacknowledged American surveillance of the Soviet Union. The incident increased international tensions and caused Soviet leader Nikita Khrushchev to cancel a much-anticipated summit with U.S. President Dwight D. Eisenhower.

Because the closed nature of Soviet society made it difficult to determine that nation's military capabilities, in 1954 Eisenhower secretly ordered the fabrication of a small number of special reconnaissance aircraft, built by Lockheed and dubbed the U-2, to secretly overfly the Soviet Union. The U-2 was an engineering marvel, essentially a glider outfitted with a jet engine and capable of flying at 70,000 feet and more than 4,000 miles without refueling. On 4 July 1956, civilians under contract with the Central Intelligence Agency (CIA) began piloting U-2 aircraft on twenty-four missions over the Soviet Union, taking photographs and gathering other electronic data. The U-2 overflights showed that the Soviets had been exaggerating their bomber and missile capabilities. Eisenhower feared that revelation of the flights could be considered a hostile action, but he believed that the need to obtain intelligence outweighed the potential risks of the U-2 program.

Although initial studies suggested that the Soviet Union's defenses would be incapable of reliably tracking or attacking the U-2s at their normal flying altitude, the planes were nevertheless monitored closely and were frequently targeted by Soviet interceptors and surface-to-air missiles (SAMs). The Soviets lodged objections with the United States after the early flights but did not complain publicly, probably because of their reluctance to acknowledge their inability to destroy the planes.

In February and March 1960, having authorized only four overflights since 1958, Eisenhower approved two missions for the coming weeks. Although he was worried about harming East-West rapport on the eve of a summit among American, Soviet, British, and French leaders scheduled to begin on 16 May in Paris, he was convinced of the need to gather details about recent Soviet intercontinental ballistic missile (ICBM) developments before the meeting. Midway through the second of these flights, the U-2 jet piloted by Francis Gary Powers was shot down by Soviet air defenses, and he parachuted into Soviet hands. The Soviets also collected—largely intact—the camera and other remnants of the plane.

To Khrushchev, this overflight was a particular affront because it occurred on a communist holiday (May Day) and because he saw it as an intentional presummit provocation. Correctly assuming that the United States did not know that the Soviets had captured Powers and secured incriminating aircraft components, Khrushchev set out to embarrass the Eisenhower administration. After the United States announced that the downed plane was a weather research aircraft, the Soviet leader publicly revealed the damning evidence to the contrary and announced his intent to try Powers for espionage. The eventual confirmation of the Americans' activities and their attempts to cover them up created an international sensation and torpedoed the forthcoming Paris summit.

Eisenhower tried to explain the overflights as regrettable infringements upon Soviet sovereignty that were nonetheless necessary to understand Soviet military capacity. He hoped that the summit would continue as planned and thus allow his presidential term to conclude on a high note by building upon the improved relations that had resulted from Khrushchev's celebrated 1959 visit to the United States. Some of Eisenhower's advisors thought that the CIA had been ill-prepared for the possibility of a downed plane and failed to advise the president of the likelihood of an interception, especially given persistent Soviet efforts to achieve such. Some aides proposed that Eisenhower avoid responsibility by claiming that the overflights occurred without his authorization, a suggestion the president rejected because it would improperly place blame on subordinates and would incorrectly suggest that underlings had the latitude to authorize such significant activity. Some officials, not privy to the details of what to do if captured, blamed Powers for allowing himself to be taken prisoner and too readily admitting to his activities.

While it is more difficult to assess Soviet reactions, many U.S. analysts believe that Khrushchev shared Eisenhower's quest for relaxed relations but faced resistance from hard-liners in the Kremlin. This forced Khrushchev to balance anger with interest in a rapprochement, although he did lash out against Pakistan and Norway, nations that he knew had facilitated some U-2 missions. When he arrived in Paris putatively for a preliminary meeting, he made it clear that he would not assent to the formal convening of the summit without a public apology from Eisenhower. The U.S. leader refused, although he renounced any further aircraft overflights. This stance was unacceptable to Khrushchev, who therefore refused to participate in the summit and canceled arrangements for Eisenhower's state visit to the Soviet Union.

Although global reaction varied as to which party was responsible for the meeting's failure (some believed that Khrushchev exaggerated his position for propaganda purposes), Eisenhower considered it a great loss. After an August 1960 show trial, Powers was sentenced to ten years' imprisonment. In February 1962, however, he was traded for Colonel Rudolf Abel, a Soviet spy being held in U.S. custody. Subsequent investigations determined that Powers had acted properly during his mission and time in captivity. By the late summer of 1960, U.S. photographic intelligence of the Soviet Union began to rely on secret orbiting satellites that passed over Soviet territory. Because they traveled through space, international law did not consider them violations of sovereign airspace.